Adjustable boring tool



April 22, 1941. J. H. FILBURN 2,239,417

ADJUSTABLE BORING TOOL Filed Dec. 26. 1939 INVENT OR.

BY fzZ.

Patented Apr. 22, 1941 UNITED STATES PATENT OFFICE ADJUSTABLE BORING TOOL John Henry Filburn, Detroit, Mich.

Application December 26, 1939, Serial No. 311,047

3 Claims.

This invention relates to machine tools and has particular reference to a boring tool.

An object of the invention is the provision of a borin tool that may be adjustably secured in position on a lathe so that it is possible at all times to keep the tool parallel with the longitudinal axis of the piece being bored.

Another object of the invention is the provision of a device which permits the use of a comparatively larger boring bar than can be used with present known devices.

It is common practice to hold the boring bar on a rocker and adjust the rocker so that the cutting part of the bar may be properly centered for boring. In boring comparatively deep holes with such apparatus the bar has to be relatively small in cross section, so that it may enter the hole in angular position as the rocker type mounting necessitates a tilt on the bar. This has certain disadvantages, which I propose to overcome.

With my improved device the bar can be almost as large in cross section as the diameter of the hole itself, for with my device the bar will enter the hole parallel and not at an angle.

The foregoing objects and advantages of the invention, and others will become more apparent as the description proceeds, reference being made from time to time to the accompanying drawing, in which drawing:

Fig. 1 is a front elevation of a device embodying my invention.

Fig. 2 is a top plan view of the device.

Fig. 3 is a sectional view taken substantially on the line 3--3 of Fig. 2.

Fig. 4 is a sectional view taken substantially on the line 4-4 of Fig. 1.

Referring now more particularly to the drawing, it will be seen that in the embodiment herein disclosed, the device consists of an L-shaped body member 6 (Fig. 1), which is adapted to be secured in the tool post of a conventional lathe. The body 6 is slotted, as at l, to accommodate the bolt 8, which is machined on the end of the boring bar support member 9.. The member 9 is bored as at I0, so that a conventional boring bar ll may be extended therethrough. A split bushing I2 is employed to accommodate bars of different diameter.

The bar support member 9 is formed cylindrical and is arranged to extend through and closely fit a bore l3 formed in the V block I4, and is adapted to be drawn inward by the lock nut l5 which engages the threads I6 of the bolt 8 at the back of the body 6. The reference character I! indicates a washer.

The short leg l8 of the body member 6 is machined, as at l9, to form a wide groove, which extends parallel to the slot I. The groove I9 is adapted to engage an offset 20 formed on the end of the V block l4 so that the said V block may be moved into different positions on the short leg I8 of the body member 6. The edges of the leg I8, along the groove [9, and the edges of the V block [4, adjacent the offset 20, are provided with teeth 2| so that the respective parts may be locked in predetermined position.

It is obvious therefore, that with a device such as described, various degrees of vertical adjustment may be accomplished with the boring bar so that it can be positioned in exact parallel relation to the hole to be bored.

Having described my invention, what I claim and desire to secure by Letters Patentis:

1. A tool holder comprising a comparatively long rectangular body member, adapted to be held in the tool post of a lathe, an angular leg on said body member, a block adjustably positioned on said leg, a V groove in said block arranged parallel to the longitudinal axis of said body member, and a bar holder element adapted to hold a boring bar in said V. groove, the said angular leg being provided with a longitudinal slot, the said block being provided with a substantially large central bore, and the said bar holder element being adapted to extend through the said bore in said block and the said slot in said angular leg.

2. A tool holder comprising a comparatively long rectangular body member, adapted to be held in the tool post of a lathe, an angular leg on said body member, a block adjustably positioned on said leg, a V groove in said block arranged parallel to the longitudinal axis of said body member, and a bar holder element adapted to hold a boring bar in said V groove, the said angular leg being provided with a longitudinal slot and a groove on one side of said leg parallel to said slot, and the said block having an offset portion adapted to travel in the groove of said leg, there being serrations on the contacting surfaces of said leg and said block adjacent to the said groove in said leg and the said offset portion of said bar, and there being a threaded element extending from said bar holder element through said slot in said angular leg and beyond, the free end of said threaded element being adapted to accommodate a nut,

3. A tool holder comprising a comparatively long rectangular body member, adapted to be held in the tool post of a lathe, an angular leg on said body member, a block adjustably positioned on said leg, a V groove in said block arranged parallel to the longitudinal axis of said body member, and a bar holder element adapted to hold a boring bar in said V groove, the said block being provided with a substantially large axial bore, and the said bar holder element comprising a cylindrical member adapted to fit into the central bore of said block, there being a transverse bore in said bar holder element adapted to accommodate a boring bar and hold the same in a position parallel to the V groove in said block.

JOHN HENRY FILBURN. 

